A typically known wind turbine is provided with wind turbine blades supported rotatably with respect to a hub via a rotational bearing such that the pitch angle of the wind turbine blades is variable, and a hydraulic actuator for rotating the wind turbine blades about the center axis of the rotational bearing.
For instance, Patent Document 1 discloses a variable pitch blade type wind turbine configured to vary the pitch angle of wind turbine blades with a hydraulic cylinder via a link.